[Radiology of cysts: Analysis and classification of pulmonary and hepato-pancreatic cysts on imaging].

Cysts are common abnormalities in imaging, exhibiting a wide range of localizations and pathophysiological mechanisms. Their classification is based on morphological and clinical criteria guiding both diagnostic and therapeutic management. This article primarily focuses on pulmonary cysts, while briefly addressing hepatic and pancreatic cysts. Pulmonary cystic lesions are often the result of infectious, inflammatory, neoplastic or lymphoproliferative processes. Thoracic computed tomography is the key diagnostic tool for their evaluation, helping to differentiate these lesions from other pulmonary abnormalities, such as emphysema or bronchiectasis. Depending on clinical and radiological features, pulmonary cysts may be associated with specific disorders including lymphangioleiomyomatosis, Langerhans cell histiocytosis, or Birt-Hogg-Dubé syndrome. Although surgical pulmonary biopsies are rarely necessary, they may be essential for definitive diagnosis when imaging fails to provide a definitive conclusion. Such biopsies should be targeted based on CT images, with adequate tissue sampling to optimize diagnostic yield. In hepatopancreatic imaging, the detection of cystic lesions with enhancement, septations, or thickened walls, in the absence of an infectious context, warrants a multidisciplinary evaluation to assess the need for targeted sampling and to refine the etiological diagnosis, particularly in cases of suspected malignancy. Close collaboration between radiologists and pathologists is essential to ensure an accurate diagnostic characterization of cystic diseases, integrating radiologic-pathologic correlations necessary for optimal patient management.